Virulence & pathogenicity of Yersinia enterocolitica under different test systems.

Eight clinical isolates of Y. enterocolitica were tested for various pathogenicity and virulence markers. Seven of the eight strains gave positive results for Congo red magnesium oxalate (CRMOX) agar test and autoagglutination test at 37 degrees C. Seven strains bound crystal violet (CV) completely at 37 degrees C but not at 25 degrees C. One strain (Y1) bound CV partially. None of the strains showed pyrazinamidase activity indicating these strains to be virulent. Cells of all but one strains were aggregated by 1.8 M and 3.2M concentration of ammonium sulphate. A good correlation between these tests and virulence was observed.